Efficient estimation of high-dimensional multivariate normal copula models with discrete spatial responses

The distributional transform (DT) is amongst the computational methods used for estimation of high-dimensional multivariate normal copula models with discrete responses. Its advantage is that the likelihood can be derived conveniently under the theory for copula models with continuous margins, but there has not been a clear analysis of the adequacy of this method. We investigate the small-sample and asymptotic efficiency of the method for estimating high-dimensional multivariate normal copula models with univariate Bernoulli, Poisson, and negative binomial margins, and show that the DT approximation leads to biased estimates when there is more discretisation. For a high-dimensional discrete response, we implement a maximum simulated likelihood method, which is based on evaluating the multidimensional integrals of the likelihood with randomized quasi Monte Carlo methods. Efficiency calculations show that our method is nearly as efficient as maximum likelihood for fully specified high-dimensional multivariate normal copula models. Both methods are illustrated with spatially aggregated count data sets, and it is shown that there is a substantial gain on efficiency via the maximum simulated likelihood method

Consideration of surge arresters for low voltage mains applications

The work presented in this report details the background to surge arresters and surge protective device components, viz., spark gaps, gas discharge tubes and metal oxide varistors. Current surge protective device technologies are detailed for several of the larger surge protective device manufacturers worldwide. Tests were performed using both 8/20 μs and 10/350 μs current impulses to verify the voltage and current response of gas discharge tubes with or without series MOVs and triggering circuits. Measurements obtained from the test setup were compared against each other, sharing a total impulse current of 35.8 kA peak using an 8/20 μs waveform and 10.2 kA peak using a 10/350 μs current impulse waveform. In the work presented, it is shown that series varistors dampened any voltage and current oscillatory behaviour superimposed from the current impulse generator due to their voltage clamping properties, which similarly do not allow any follow current to flow after a surge has subsided. No effect was seen by using a single varistor or a many parallel mounted varistors in series with a gas discharge tube. By using three electrode gas discharge tubes with a triggering circuit, the clamping voltage was reduced, as the gas tubes reacted faster than an equivalent circuit without a triggering module, which has the advantage of reducing the protection level for the protected equipment

Framization of the Temperley-Lieb Algebra

We propose a framization of the Temperley-Lieb algebra. The framization is a procedure that can briefly be described as the adding of framing to a known knot algebra in a way that is both algebraically consistent and topologically meaningful. Our framization of the Temperley-Lieb algebra is defined as a quotient of the Yokonuma-Hecke algebra. The main theorem provides necessary and sufficient conditions for the Markov trace defined on the Yokonuma-Hecke algebra to pass through to the quotient algebra. Using this we construct 1-variable invariants for classical knots and links, which, as we show, are not topologically equivalent to the Jones polynomial.Comment: 30 page

Optimization of cut surface quality during CNC Plasma Arc Cutting process

Optimization of cut surface quality during CNC plasma-arc cutting (PAC) of mild steel plates is presented. Using design of experiments (DOE) the optimum process parameters are estimated. The process parameters tested include cutting speed, cutting height and arc voltage. Analysis of means (ANOM) and analysis of variances (ANOVA) were used in order for the effect of each parameter on the surface quality to be assessed

Inward FDI in Bulgaria and its policy context

After the fall of the country's communist regime, Bulgaria faced great political instability, changing prime ministers eight times between 1990 and 1997. Three economic crises were associated with slow economic growth or even recession as well as high inflation rates that weakened the Bulgarian economy and discouraged inward foreign direct investment (IFDI) flows in the 1990s. The establishment of a currency board in July 1997 stabilized the economy and greatly increased foreign participation in the privatization process, leading to a major increase in IFDI flows. The entry of Bulgaria into the European Union (EU) in 2007 was a catalyst for IFDI. Bulgaria received US$28 billion of IFDI flows in 2007-2010, compared to only US$ 24 billion during the transition period from 1990 to 2006. A low corporate tax rate (10%) and EU membership have played a decisive role in attracting IFDI to Bulgaria

Determinants Of Barries To Quality Of Direct Foreign Investments Evidences From South & East Asian Economies

The objective of this paper is to examine whether FDI inflows in South & East Asian economies posses any barriers which are deterring to attract FDI of their actual potential? If so, what are those various set of barriers? These questions are addressed in this study using cross section time series data for 17 South and East Asian economies from 1996 to 2005.http://deepblue.lib.umich.edu/bitstream/2027.42/64376/1/wp910.pd

Molecular ecology and fitness of striped (Stenella coeruleoalba, Meyen, 1833) and common (Delphinus delphis, Linnaeus, 1758) dolphins

In this study the molecular ecology and fitness of two Delphinidae species, the striped dolphin (Stenella coeruleoalba) and the common dolphin (Delphinus delphis), were investigated in the Mediterranean Sea and Atlantic Ocean. This thesis provides a comparative assessment of the striped and the common dolphin, using molecular methods regarding the genomic diversity and parasite resistance. The striped and the common dolphin have a world-wide distribution, inhabiting pelagic waters and differ with respect to population structure within the study area. The aim is to reveal different patterns of genetic diversity and fitness in the species that shows greater populations structure. In order to test this, my analyses structure was a) to analyse the population structure of the striped dolphin in the Mediterranean Sea and Atlantic Ocean and compare structuring patterns with previous published studies, b) to examine the heterozygosity fitness correlation for both species, using neutral and non-neutral markers and specific parasites that are important of animal’s health. In this context this study tests that local populations show stronger relationship between genetic diversity and fitness. This study suggested that different methods regarding to power and studied subareas show a fine-scale structure beyond that reported previously in striped dolphin populations. A key new finding is the structuring pattern in the Atlantic Ocean, where populations from Scotland and the Biscay Gulf were isolated from the one in Ireland. Also, the Ionian Sea samples grouped with the western Mediterranean, which could either be an effect of the small sample size from the Ionian Sea, or reflect a boundary closer to Greece, dividing the basins of the Mediterranean for this species. In this study I found differences between the two hosts with respect their genetic diversity and parasite loads for both nuclear and functional loci. I also found that evidence for a heterozygosity fitness correlation was strongest for females, and this was true both for the correlation with genomic diversity as assessed using neutral markers, and for the functional immune system gene. This observable association suggests that parasites may act as an energetic stress, and may reflect the non-identical pathogenesis of parasites and their ability to inflict damage through the hormone profiles. Results illustrate potentially important interactions between genetic drift and selection, and provide specific information that will be valuable towards the conservation and management of diversity in these species